The present invention relates generally to box spring bedding assemblies of the type adapted for use as a mattress foundation and, more particularly, to a wire grid for use in such a box spring bedding assembly to support an array of coil springs.
Conventional box spring bedding assemblies are of a relatively common uniform construction having a rectangular base frame on which a spaced array of multiple coil springs are mounted in upstanding disposition in a spaced array, with a correspondingly rectangular wire grid connected to a top coil of each spring, the entire construction being upholstered with a suitable fabric or other appropriate covering. Typically, the base frame is fabricated of wood, having a rectangular outer sub-frame with a longitudinal frame member extending the length of the sub-frame midway across its width and with a plurality of lateral frame members, commonly referred to as slats, extending widthwise across the sub-frame in parallel relation to one other at spacings along the length of the sub-frame. The plural coil springs of the box spring assembly are arrayed in widthwise-extending parallel rows across the lateral slats and the laterally-extending end members of the sub-frame.
Conventional box spring assemblies of this basic construction have traditionally been manufactured in varying grades, differentiated primarily according to the number of coil springs incorporated in the box spring assembly which correspondingly affects the overall firmness and anticipated useful life of the box spring assembly. Typically, a greater number of slats are provided in the base frame of box spring assemblies which are to incorporate a greater number of coil springs. For example, with box spring assemblies of a stand size commonly called "full size", many manufacturers produce box springs in three differing grades utilizing three differing base frame constructions each with a differing number of lateral slats (e.g., six, seven, or eight slats) in order to achieve differing arrays of differing numbers of coil springs for varied degrees of firmness. Similarly, box spring assemblies in other sizes commonly referred to as "twin", "queen", and "king" (i.e, two "twin" box springs) sizes, are also commonly produced in differing grades generally differentiated only by the number of slats and springs utilized in the box spring.
Since the base frame of such box spring assemblies are constructed of wood, a manufacturer's fabrication of three or more differing box spring structures with differing numbers of slats does not significantly increase the manufacturer's overall costs in comparison to the costs associated with producing one grade of box spring. However, on the other hand, each differing box spring construction requires a differing wire grid to interconnect the top coils of the particular array of coil springs, which does significantly increase the manufacturer's costs since such wire grids cannot be as easily and inexpensively manufactured in differing construction. Typically, such wire grids are acquired by box spring manufacturers from a third party, necessitating that the manufacturer maintain separate inventories of each differing wire grid, whereas in contrast the box spring manufacturer would typically fabricate the base frames itself from stock pre-cut wooden frame members and slats which do not vary in size from one grade of box spring to another.